Fluid actuating device



D. A. PRICE ETAL FLUID ACTUA'I'ING DEVICE Dec. 9, 1941.

Filed Jan. 22, 1940 &7 BY

QM ma and the stufiing Patented Dec. 9, 1941 FLUID ACTUATING DEVICE Donald A. Price and Heights, 11].,

Shoe and Foundry Company,

Perry I. Nagle, Chicago assignors to The American Brake New York, N. Y.,

a corporation of Delaware Application January 22, 1940, Serial No. 314,999

Claims.

The present invention relates to improvements in fluid actuating devices; and more in particular to improvements in centrifugal pumps.

One of the objects of the present invention is to provide a novel arrangement for certain operating elements of a centrifugal pump or the like to substantially eliminate eddy currents in the fluid disposed within the pump and in contiguous relation with the said operating elements whereby wear on said elements is greatly decreased and the efliciency of the device is increased.

According to present constructions, considerable attention has been given to the construction and arrangement of the elements on thedischarge side of fluid actuating or impelling devices forincreasing the hydraulic efliciency thereof. On the other hand, these devices are subjected to criticism on the score that although the efllciency in many cases has beenincreased by incorporating such improvements, nevertheless no attention whatsoever has been given to other parts of the device to decrease wear on the operating elements thereof, with corresponding increase in the life of the said device.

As is well understood in the art, such fluid actuating or impelling devices as herein contemplated operate on the principle of imparting centrifugal motion to the incoming fluid ad discharging the said fluid at the periphery of the fluid impeller at increased pressure over the pressure maintained on the intake side of the said device. As a matter of fact, the pressure at the discharge end of the device may be as much as 100 pounds to the square inch or more, whereas the pressure of the fluid on the intake side of the device may be a negative pressure, the relation of the two depending, of.course, upon the design of' the particular device and its speed of operation. Nevertheless there is always a pressure differential between the discharge and intake sides of the said device.

As a further factor in a consideration of this type of device, a clearance space is necessarily present between the fluid-actuating or impelling device and the, adjacent side wall or walls of the casing. Because of the pressure differential between the discharge and intake for the said device on the one box on the other side, flow of fluid takes place therebetween in the direction of the said intake and the stufling box and through the restricted clearance spaces formed between the impeller and the side walls of the casing. Accordingly, because of the particular disposition of the impeller with respect to the contiguous side and between the discharge parts of the casing therefor resulting in these restricted clearance spaces throughwhich flow of fluid necessarily takes place, and further, because of the action of the impeller or fluid actu- 5 ating element operating at high speeds, violent whirls and eddy currents are produced between the said impeller and the side walls of the easing, which fluid disturbances cause considerable wear on the surfaces of the impeller and easing subjected thereto, and particularly at and adjacent the restricted spaces between the impeller and the contiguous stationary casing. This condition is aggravated when the fluid being discharged through the device contains sediment or other foreign substances, and particularly when impelled at high speeds which cause rapid deterioration of the parts, requiring frequent replacement or repair thereof to condition the device for maximum and eflicient performance.

Another factor particularly relating to the excessive wear which is experienced under the operating conditions alluded to above at the restricted spaces between the impeller and casing is the abrupt change in velocity or direction of the fluid at the said restricted clearance spaces because of the fluid seal provided thereby. That is to say, because of the abrupt changes in crosssectional area of the passages between the impeller and casing due to the restricted clearance spaces, the velocity of the fluid passing through said passages is abruptly changed, thus intensifying the eddy currents and whirls within said passages, which condition further amplifies the eroding characteristics of the material-laden fluid being impelled and accordingly causing excessive'wear at and adjacent the said restricted spaces. All of said detrimental factors are more pronounced at the restricted clearance space between the discharge and intake than between 40 the discharge and the stufling box.

The present invention has proceeded with these inherent defects of present constructions in mind and on the theory that although flow of fluid from the discharge to 45 stufling box side of the unit could not be dispensed with and completely eliminated, nevertheless adjacent and contiguous surfaces of cooperating elements of the device could be so constructed and arranged as to practically eliminate eddy pockets and abrupt changes which would lead to eddy currents the fluid in the passageways between the operating elements, and to provide for the flow which necessarily takes place in the direction of the intake and stufling box for the device in such a the intake and and violent whirling of way as to cause a more uniform flow of fluid, with gradual changes in velocity and direction at the restricted spaces, thus eliminating all causes for excessive wear which has taken place heretofore at and adjacent the restricted spaces on the cooperating elements of the device at those points.

It is therefore an object of the present invention to provide improvements in fluid actuating devices of the type herein disclosed whereby eddy currents and violent whirls of fluidare substantially eliminated during operation of the device at and adjacent the said restricted spaces, thus resulting in practically eliminating the wear which has taken place heretofore at those points.

More particularly, the present invention contemplates an arrangement of the contiguous surfaces of the impeller and the stationary casing in which the same operates whereby said surfaces are of streamlined formation, gradually merging into the surfaces defining the restricted space or spaces at the clearance between the said impeller and said casing. As a further object of the present invention, the flow line contours of the said impeller and contiguous casing at and adjacent thesaid restricted spaces are such as to provide for gradual changes in the velocity and direction of fluid flow from one part of the device to the other, as hereinbefore referred to.

A stillfurther object of the present invention is to provide flow line contours for adjacent surfaces of operating elements of a centrifugal pump which gradually merge with the surfaces defining restricted clearance spaces which may exist in the device.

The present invention further comprehends a novel arrangement in a fluid actuating device for the impelling or actuating element and its power driven shaft, which assembly embodies as an improvement a protecting sleeve, the said shaft and sleeve being connected to the impeller or actuating element by way of opposed cooperating threads whereby the impeller and protecting sleeve may be removed from the shaft without affecting or disturbing in any way the operative position of the said shaft. More particularly, the said assembly comprising the impeller, its driving shaft and the protecting sleeve is embodied in a device wherein a stufling box is used in cooperative association with the said sleeve to prevent leakage between the casing in which the impeller operates and the said shaft, the particular connection between the impeller and its shaft and protecting sleeve likewise comprising the opposedcooperating threads to facilitate the removal of the impeller and the said sleeve from the assembly without disturbing or affecting the operative position of the said shaft.

Other objects, features, capabilities and advantages are comprehended by the invention, as will later appear and as are inherently possessed thereby.

Referring to the drawing: The flgure is a view partly in elevation and partly in cross section disclosing a centrifugal pump embodying improvements in accordance with the present invention.

Referring now more in detail to the drawing, the improvements constituting the present invention are disclosed as being incorporated in a centrifugal pump comprising a base 2 having pedestals or standards 4 and 6 adapted to support an impeller housing 8 and associated mechanism and a bearing stand Ill, respectively. The

housing 8 is of multi-part construction, including opposed side walls l2 and I4 to which is attached an outer peripheral housing part l6 connected in any desired manner thereto and forming a fluid compartment l8 in which operates an impeller or fluid actuating element 20. The housing assembly further includes the intake element 22 and the plate element 24, the former being provided with an intake passageway 26 and being provided with securing means 28 to be secured to an intake conduit or duct for delivering fluid to the device, and the latter of which is connected to sealing mechanism or stuffing box 30 for a shaft 32 which is power-driven and connected to the impeller 20. The parts of the pump housing, as explained above, may be connected by way of a plurality of bolts, such as 34, cooperating with the various elements through spaced lugs such as 38 and openings such as 38, or by way of spaced and opposed lugs such as 40 and 42, suitable gaskets, indicated as H, being provided as needed to secure water-tight joints between the various elements. The duct 26 communicates with an opening 46 formed in the side wall l2 to form an intake leading axially into the impeller 20. This impeller 20 is of the shrouded or closed type, including a hub 48 having a threaded bore threadedly engaging the shaft 32 as at 50, upon which hub is mounted the impeller constituted by opposed walls 52 and 5| between which are provided a plurality of curved blades such as 56 and 58. These blades form radially extending passageways therebetween which merge at one end into the opening 60 which communicates with the opening 46, and at the other end communicate with chamber ll whereby fluid impelled by said impeller is discharged tangentially therefrom at its periphery into the said chamber and outwardly through a discharge conduit communicating therewith.

The shaft 32 threadedly conected to the hub 48 at one end thereof extends outwardly from the housing assembly and is mounted for rotation within the bearing stand I ll comprising the housing 62 which completely encloses spaced antifriction bearing units El and S6 for supporting and positioning the shaft during its operation and for maintaining its proper alignment whereby the said impeller will be properly operated within the housing assembly.

The shaft 32 is embraced adjacent its threaded end. 50 by a sleeve 68 which extends through the sealing device 30 and is in sealing engagement with a plurality of compressible washers suchas III of the said device for maintaining a tight joint between the shaft 32 and the housing assembly 8. This sealing device further includes a gland follower I2- havlng an annular part 14 disposed to compress the washers II, and is adjusted into any desired position by means of a plurality of bolts or the like 16. The sealing device is further provided with a pipe 'll'communicating with the interior thereof by way of duct whereby water may be introduced to provide.a water seal for said device.

As explained heretofore, operating conditions require certain clearance spaces between the impeller 20 and the side walls I2 and ll of the housing assembly. In the herein illustrated example of a device embodying improvements constituting the present invention, such clearance spaces are shown on one side of the impeller 20 as at 82 between side wall l2 of the housing and the side wall 52 of theimpeller, and as at 84 between the side wall 64 of the impeller and the side wall I4 01 the housing assembly. Heretofore, in structures of the type herein disclosed, considerable difllculty has been experienced in the excessive wear and erosion which takes place adjacent such clearance spaces as 82 and 84. This wear and erosion are due primarily to the formation of eddy currents and violent whirls in the passageways between the impeller and the contiguous stationary casing, as for example at 86, 88 and 88, due in part to the rapid movement imparted to the fluid in such passageways by the rapidly rotating impeller 28, and in part to the flow of fluid from the discharge end of the housing toward the intake part on one side of the housing due to the pressure differential at these points and to flow to the stuffing box on the other side of the housing, it being recognized that a large positive pressure is present at the discharge end of the housing, and atmosphere or sub-normal or other pressures of less intensity on the intake and stumng box sides of the said device. This situation is aggravated, particularly on the intake side, to a large degree by the presence' of foreign material in the fluid being impelled, such asis present under most conditions where a device of this kind is used, and particularly in the pumping of sludge and the like which includes a large amount of solid particles which, at high velocities, cause considerable damage to the parts of the pump where abrupt changes in velocity take place, as would be experienced at and adjacent the said clearance spaces 82 and 84.

In order to greatly decrease this wear and erosion at the points indicated, the opposed wall surfaces 82 and 84 of side walls I2 and 52, respectively, and defining the passageway 86, are formed with flow line curvatures without abrupt changes whereby uniform flow of fluid may take place ther'eover, the said surfaces merging gradually as at 86 into the surfaces of the side walls I2 and 52 defining the clearance space 82. This streamlined formation for the said surfaces and their gradual merging into the surfaces defining the restricted clearance space 82 between the impeller and contiguous side wall of the casing substantially eliminates any tendency for whirls and eddy currents to be created which would otherwise cause excessive wear and erosion of the material for the side walls I2 and 62 adjacent said clearance spaces.

On the other side of the impeller the passageway 88 is defined by opposed surfaces 88 and I88 formed onthe side walls 64 and I4 of the impeller and housing, respectively, the said surface 88 in this particular instance being curved as at I82 to gradually decrease the sectional area of the passageway 88 to merge with the clearance space 84 for the same purposes which have been above explained in respect of the structure on the other side of the impeller. In respect of the assembled relation of the impeller and the side plate I4, however, it will be noted that the clearance space 84 is formed in spaced relation to the shaft 32, and that another passageway 88 of relatively large cross-sectional area is provided between the impeller and the side wall I4. Because of the relatively large cross-sectional area of passageway 88 which permits a decrease in the velocity of fluid passing toward the stuffing box 38 through the restricted clearance space 84, the said surfaces 88 and I88 of the said side walls 64 and I4, respectively, are of streamlined contour or formation whereby the said passageway 88 has its cross-sectional area gradually increased from the restricted clearance space 84 inwardly and radially toward shaft 32, thus eliminating all abrupt changes which might cause eddy currents or whirls in the said assageway, resulting in excessive wear to the adjacent parts upon operation of the impeller at high speeds. A gradual divergence of the wall surfaces 88 and I88 prevents abrupt changes in the velocity of the fluid passing through restricted clearance space 84, which abrupt changes are in part the cause for the excessive wear and erosion which have been referred to hereinbefore.

With the flow line contours above described, eddy currents and violent whirling motions are substantially eliminated within the fluid in the passageways designated upon rotation of the impeller. Thus a large part of the excessive wear heretofore experienced has been eliminated, which results in more eflicient operation of the device over extended periods of time without requiring replacement or repair of the various operating elements of the unit.

As a further improvement embodied in the centrifugal pump herein described, but equally adapted for other fluid impelling devices, such as reciprocating pumps or hydraulic presses, reference is hereby made to the manner in which the protecting sleeve 68 and operating shaft 32 are connected to the impeller to expedite removal of the said protecting sleeve 68 and impeller 28 without disturbing the adjustment or position of the said shaft 32. This removal is necessitated because of the need of repairs or replacements to the various elements, and particularly the protecting sleeve 68, as well as the impeller or other parts of the housing, and it is highly desirable to provide a construction which can be disassembled with ease and facility and the parts repaired or replaced without loss of time. In order to accomplish this result, the various parts of the housing are readily disconnected to secure admittance to the fluid chamber I8 and to gain access to the impeller 28.

The impeller 28 is connected to the protecting sleeve 68 by way of cooperating threads as at I84, the threads I84 being opposed to the threads 58 by which the shaft 32 is likewise connected to the impeller. That is to say, the threads 58 may be cut as left-hand threads, whereas the threads at I84 are cut as right-hand threads, or vice versa, and with equal pitches whereby, when the impeller 28 is removed from shaft 32, the sleeve 68 will be removed simultaneously without disturbing in any way the alignment or mounting for the shaft 32. The protecting sleeve 68 normally rotates with the shaft 32 and is held in association therewith by way of a set screw I86, which further connects a water flinger I88 to the said sleeve 68. Because of the opposed threads at 58 and I84, a further advantage is secured in that when the sleeve 68 is rotating, the frictional drag of the washers 18 the sleeve more tightly into the impeller, securing it in operation against relative motion of the shaft. While we have herein described and upon the drawing shown an illustrative embodiment of the invention, it is to be understoodthat the invention is not limited thereto but may comprehend other constructions, arrangements of parts, details and features without departing from the spirit of the invention.

We claim: I

1. In a centrifugal pump, the combination of an impeller, a casing having intake and discharge means, said impellerbeing mounted for on the sleeve tends to screw upon operation of said impeller.

rotation in said casing and having a substantially sealing relation with said casing adjacent said intake means through the medium of a restricted clearance space, and said impeller and the adjacent casing having flow line contours gradually merging toward and into said clear-,

ance space.

2. In a centrifugal pump, the combination of an impeller, a casing having intake and dischargemeans, said impeller being mounted for rotation in said casing and having a substantially sealing relation with said casing adjacent said intake, means through the medium of a restricted clearance space, and said impeller and the side wall of said casing adjacent thereto having substantially radially extending flow line contours converging gradually toward and into said clearance space to provide for gradual change in velocity of fluid within said pump.

3. In a centrifugal pump, the combination of an impeller, a casing therefor having intake and dischargemeans, astufling box in association with said discharge means, said impeller being mounted for rotation in said casing and having a substantially sealing relation with said casing adjacent said intake means and stufling box through the medium of restricted clearance spaces, and said impeller inwardly of the periphery thereof and the opposed walls of said casing having flow line surfaces free from abrupt changes gradually merging with said restricted clearance spaces to eliminate the formation of eddy currents in the fluid within the said 4. In a centrifugal pump, the combination of 'an impeller, a casing having intake and discharge means, a stufllng box in association with said discharge means, said impeller being mounted for rotation in said casing and having a substan-' tially sealing relation with said casing adjacent said intake means and stufling box through the medium of restricted clearance spaces, the impeller and said'casing having flow line contours gradually merging into the restricted space adsaid housing and being connected to said element, means for operatively positioning said shaft with respect to said element, a stufllng box for said shaft, a sleeve for protecting said shaft against wear connected at one end to said element and extending through said stuffing box, said connections comprising interengaging right and left handed threads whereby removal of said element and sleeve from said shaft can be effected without disturbing the operative position of said shaft.

momma. PRICE. PERRY I. NAGLE. 

